Myelin from both the bovine and human central nervous system is being isolated by different gradient centrifugation techniques to obtain preparations of the highest purity possible. The presence of protein kinases(s), which modify the myelin basic protein, is being investigated in these preparations. Once the presence of the kinasee(s) in myelin is established, methods are to be devised to solubilize the kinase(s) from the membrane. The kinases will be purified to study their physico-chemical properties.